on the edges of the er ##od ##ing mountains , stretching from shetland to the southern mora ##y firth . the structure of papa st ##our is largely made up of ashes and lava ##s from volcanic activity associated with this period , including bands of solid ##ified volcanic ash and lava ( r ##hy ##oli ##te ) , but there is also a devon ##ian fish bed at lamb ##a banks . there are numerous large boulders deposited by pleistocene g ##la ##ciation . erosion of the soft volcanic rocks by the sea has created an extraordinary variety of caves , stacks , arches , blow ##holes , cliffs , vo ##es and geo ##s that are amongst the finest in britain . the ' ho ##ll
on the edges of the eroding mountains, stretching from shetland to the southern moray firth. the structure of papa stour is largely made up of ashes and lavas from volcanic activity associated with this period, including bands of solidified volcanic ash and lava ( rhyolite ), but there is also a devonian fish bed at lamba banks. there are numerous large boulders deposited by pleistocene glaciation. erosion of the soft volcanic rocks by the sea has created an extraordinary variety of caves, stacks, arches, blowholes, cliffs, voes and geos that are amongst the finest in britain. the'holl